In article ,
Teignmouth writes:
Am I right in saying that as it's been zonal now for several weeks
over the the winter solstice period, when above 70N there is no
daylight, the cold has been locked in the upper atmosphere of the
Arctic, getting colder & colder, with no incursions of real cold in to
the more temperate latitudes at the surface?

ISTR that around the middle of December the blocking anticyclone which
had been giving the UK cold weather shifted further east, with the
result that we had a succession of lows grinding to a halt in our
vicinity. After another week or so the anticyclone either vanished
altogether or retreated so far east that it was no longer a factor, and
since then it's been relentlessly zonal.

So as the warm air from the tropics, that is being advected up the
western side of the UK by the High Pressure over Biscay into the
Artic regions rises through the atmosphere, dislaces the cold Arctic
air high in the upper polar atmosphere causing a SST, the now
extremly cold & dense polar air sinks to the surface & heads South
to replace the void left by the warm air from the tropics that first
headed North?

I don't know enough to say that's incorrect, but it doesn't seem
convincing to me.
--
John Hall

"Whenever people agree with me I always feel I must be wrong."
Oscar Wilde